Bacterial lung superinfections uncommon among people who died with COVID-19
Up to 32% of people who died with COVID-19 had a bacterial lung superinfection, according to findings from a review of postmortem studies.
Researchers said the review, which uncovered an “uneven” quality of data among such studies, showed that bacterial lung superinfections “complicated a minority of COVID-19 cases globally over the first months of the pandemic, and they were uncommonly the cause of death.”
“There is still a lot of uncertainty about the extent to which bacterial superinfections complicate COVID-19, and the occurrence of antimicrobial-resistant infections,” Cornelius (Neil) J. Clancy, MD, associate professor of medicine and director of the extensively drug-resistant pathogen lab and mycology program at the University of Pittsburgh, told Healio.
“In part, this is because many studies of COVID-19 patients have not used rigorous criteria in defining or classifying bacterial infections, and superinfections are difficult to diagnose clinically because SARS-CoV-2 infection itself causes comparable signs, symptoms and organ disease,” Clancy said. “We hypothesized that postmortem tissue studies would afford an alternative route to getting at questions about COVID-19-associated bacterial infections.”
Clancy and colleagues reviewed postmortem studies of patients with COVID-19 published through Sept. 26, 2020, for histopathologic findings consistent with bacterial lung infection. According to the study, 621 patients from 75 studies were included.
They said the quality of data was uneven “likely because identifying superinfections was not a major objective in 96% of the studies.” They found that histopathology consistent with potential lung superinfection was reported in 200 of 621 (32%) of patients.
According to the study, the types of infections were pneumonia (95%) 75% of which were localized to a specific area as opposed to being more broadly found in the lungs abscesses or empyema (3.5%) and septic emboli (1.5%). Superinfections were proven by direct visualization or recovery of bacteria in 25.5% of potential cases and 8% of all patients in postmortem studies, Clancy and colleagues reported.
According to the study, pathogens included Acinetobacter baumannii, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. Overall, lung superinfections caused the death in 16% of patients with potential bacterial infections “in whom a cause of death was assigned,” and only 3% of all patients with COVID-19, Clancy and colleagues reported.
Among studies with available data, 79% of patients received antimicrobial treatment, with the most common agents being beta-lactam/beta-lactamase inhibitors (48%), macrolides (16%), cephalosporins (12%) and carbapenems (6%).
“Bacterial lung infections occur in a minority of patients dying with COVID-19, most cases are localized and of unclear clinical significance in the face of COVID-19-related lung pathology, and they are rarely the cause of death,” Clancy said. “While patients with COVID-19 are at risk for bacterial infections, like all hospitalized patients and those in ICRs, the data draw attention yet again to the importance of antimicrobial stewardship. Most patients with COVID-19 will not develop bacterial superinfections, and they do not need antibiotics.”